Casing head equipment for bore holes or wells



1938- 1.. M. c. SEAMARK 2,127,312

CASING HEAD EQUIPMENT FOR BORE HOLES OR WELLS Filed 001;. 26, 1934 3 ShetS-Sh66t l Inventor 41mm; y

.dttarney.

Aug; 16, 1938. c SEAMARK 2,127,312

CASING HEAD EQUIPMENT FOR BORE HOLES OR WELLS Filed Oct. 26, 1934 3 Sheets-Sheet 2 Attorney.

Aug. 16, 1938. M. c sEAMARK 2,127,312

CASING HEAD EQUIPMENT FOR BOREHOLES 0R WELLS Filed Oct. 26, 1934 5 Sheets-Sheet 3 Inventor mum y a). E. W

Attorney.

Patented Aug. 16,1938

UNITED STATES CASING new EQUIPMENT FOR Boas HOLES on WELLS Lewis Mervyn Cecil Seamark, Radfords, Dawlish,

England Application October 26, 1934, Serial No. 750,218 In Great Britain June 15, 1934 6 Claims.

This invention relates to casing head equipment for bore holes or wells of the kind in which a massive elastic sleeve is employed through which connected sections of the casing or drill stem or the like may be inserted and withdrawn without escape of oil or gas and by which boring may be continued while the well is under pressure, and the invention has especially for its object to ensure the gas and liquid tightness of the sleeve under high pressures.

According to the invention a casing head equipment for bore holes or wells is provided comprising the casing, a massive elastic packing sleeve within the casing through which the connected sections of the casing tube, drill stem or the like may pass for insertion into the bore hole or well or for withdrawal therefrom, one end of the sleeve being capable of axial movement with respect to the other end and means comprising a piston and cylinder device or the equivalent for the axial compression and consequent inward contraction of the sleeve under the pressure exerted by a fluid pressure medium whereby a tight joint may be made around the connected sections on the deformation of the sleeve, it being understood that the sleeve is restored to its original form on the axial stress imposed upon it being with drawn.

The fluid pressure medium, used for the application of axial pressure upon the massive elastic sleeve may be derived from a hydraulic accumulator or from any other source such as the pressure in the bore hole or well, but hydraulic pressure is in general preferred having regard to the convenience and facility of regulation to the extent required to ensure gas and liquid tightness under the conditions of operation.

It will be understood that the massive elastic sleeve is not subject to pressure directly applied externally and radially to the sleeve periphery, and thus means are not necessarily required for the reinforcement of the sleeve or for ensuring the retention of the ends of the sleeve within the stationary or rotating casing against the stresses imposed upon the sleeve consequent upon pressure being directly applied externally and radially imposed.

The invention however comprises a modification in which a second elastic packing sleeve is mounted in position beneath an elastic packing sleeve that is adapted for axial compression and inward contraction under the pressure exerted by a fluid pressure medium in the manner described, the second packer comprising an elastic sleeve adapted for use alternative and suppletional features and the conditions of method I which are hereinafter described.

The invention is illustrated by way of example in the accompanying drawings in which:-

Figures 1 and 2 are respectively a vertical sec-,- tional elevation and plan of a packer" or blowout preventer of static type constructed for use according to the invention.

Figures 3 and 4 are respectively a part sectional elevation and half plan of a blow-out preventer of rotary type constructed according to the invention.

Figure 5 is a detail sectional view of the U leather mounting employed in the construction of Figures 1 and 3.

' Figure 6 is a diagrammatic elevation partly in section of a modification of construction.

In carrying the invention into effect a massive elastic sleeve I may be employed relatively long and advantageously made of indiarubber as illustrated in Figures 1 and 3 which respectively represent a blow-out preventer or packer of static type and a blow-out preventer of rotary type. This massive elastic sleeve 1 may be moulded in one piece of a cylindrical form externally, and the central bore may be of such a form that the diameter of the bore is gradually increased towards the respective ends, whereby the sub stance of the sleeve in the middle at or about the part indicated f protrudes inwardly. The sleeve I may however be advantageously provided, for convenience and economy in manufacture, of separate rings or parts of indiarubber applied one upon the other. These rings or parts may be formed with parallel flat faces and the central hole in the respective rings may be coincident and reduced in diameter towards the middle of the sleeve, while their external diameter may be uniform. The sleeve or the constituent rings or parts thereof may be slit in a plane or planes parallel to its longitudinal centre line or at an inclination thereto and the rings or parts set so as to break joint. Furthermore when providing the sleeve of separate rings or parts, these may be provided to interengage, as for example bythe provision of coincident annular cavities and ribs of corresponding form on opposing top and bottom contact faces of adjacent rings or parts. Similarly the central hole orbore of the sleeve or the constituent rings or parts thereof may be provided at the central hole therein of a curvilinear or other shape in vertical cross-section, the part of the hole or bore at or about the middle being advantageously of reduced diameter, and the internal faces of such form that the bore of the composite sleeve flares outwardly at the respective ends.

The stationary casing c (Figure 1) or the rotating casing g (Figure 3) in which the massive elastic sleeve f is mounted may at the lower end he provided with an inwardly extending circular fiange h yielding a central hole 71 that may be of a diameter corresponding to the internal bore of an annular piston a mounted upon or engaging the sleeve 1 at its upper end the central hole h being coincident with the internal bore of the piston. In the inwardly extending circular flange h an annular cavity h? of a dovetail transverse cross-sectional shape is provided adapted for the reception of the lower part of the sleeve f that is provided of an increased internal and reduced external diameter and of a corresponding dovetail cross-sectional shape by which the sleeve f at its lower end is adapted to be held by the engagement of its lower part within the annular cavity h of corresponding transverse cross-sectional shape.

The upper part of the sleeve f is provided of a similar shape to its lower part and its upper part is also provided of a dovetail transverse crosssectional shape for engagement within an annular cavity a forming a corresponding annular rim 0. at the lower end of the piston a; the annular cavity being of a dovetail transverse cross-sectional shape corresponding to that of the upper part of the sleeve.

It will be understood that the lower part of the piston a in engagement with the sleeve is advantageously provided of an external diameter corresponding to that of the central cavity in the stationary casing c (Figure 1) or in the rotating casing g (Figure 3) in which the sleeve 1 is mounted, and that the annular'piston a is provided of a larger diameter at its upper part to present a top face that is subject to the fluid pressure medium, whereby axial pressure is imposed upon the sleeve f by the piston a in the manner hereinbefore described.

In carrying the invention into effect in the use of such a sleeve and piston device within a casing head equipment adapted to serve as a static packer as illustrated in Figures 1 and 2 of the accompanying drawings, the annular piston 11 may be provided integral with or connected to a tube b that extends upwardly out of the stationary casing c, and is adapted at its upper end to serve for bearing the weight of the connected sections of the drill stem or the like suspended within the bore hole, as described in the specifications of the prior Patents Nos. 1,942,366 and 1,902,906, but the upper part of the. stationary casing c is adapted for the reception and operation of the annular piston a provided as hereinbefore described, whereby the massive elastic sleeve I may be put under axial pressure in normal conditions of operation. For this purpose the upper part of the stationary casing c is provided of an enlarged diameter for the reception of an annular cap or closure fitting d, the lower part of which is formed with an integral and concentric cylindrical wall d of smaller diameter than the top of the cap adapted to form with the annular piston a an annular piston cavity e beneath the top of the annular cap d, within which the annular piston a is adapted to move to the extent necessary to its function in applying axial pressure upon the sleeve f. The annular cap or closure fitting d is provided with an internal annular recess near its upper part for the reception of a gland ring (1 held in position by studs by which packing d may be compressed within the internal annular recess to maintain a tight joint around the upwardly extending tube b.

The annular cap or closure fitting (I may be secured in position by means of bayonet slot devices or the equivalent or by its cylindrical wall (1 being externally screw-threaded to enter at the enlarged open upper part of the casing c and to engage a corresponding internal screw thread, whereby that outwardly extending part of the annular cap or closure fitting extending beyond the cylindrical wall d is applied with pressure upon the top of the peripheral wall of the casing c. a jointing ring of indiarubber or other jointing material being interposed, and set within an annular groove upon the top face, so that thus a tight joint is made on the annular cap or closure fitting d being applied in position.

Radial holes such as (1 may be provided within which tightening toggles may engage or other means provided for tightly closing the annular cap or closure fitting d within the casing and upon the jointing ring 0 whereupon a locking piece (1 of rectangular form may be mounted within recesses of corresponding form and coincident position on the peripheral faces of the cap d and easing c, as a simple means of positively and immovably securing the cap in its final position.

A transversely extending channel d is provided in the annular cap or closure fitting d communicating at one end with a vertical channel (1 opening at the underface of the cap or fitting d, and at the other end adapted by a fitting d for connection with a hydraulic accumulator, or with the bore hole, by which the fluid pressure medium may thus be admitted into the cavity beneath the cap or fitting d in position above the annular piston a. By such means it will be understood that the fluid pressure medium may be admitted under regulation to cause the downward movement of the annular piston a to apply axial pressure upon the sleeve f for its compression and inward contraction, and to ensure a tight joint under the varying conditions that may prevail.

An air release screw-threaded plug 1 (Figures 1 and 2) may be mounted on the top of the annular cap or closure fitting d for filling with the fluid pressure medium, the plug 9 being mounted above a passage d opening into the channels (1 and d". A similar pressure release plug may be provided for the release of pressure or fluid from the annular cavity e or from beneath top part of the piston a. For this purpose one or more vertical channels indicated in dotted lines at 11 (Figure 1) may be provided at a position or positions out of alignment with the channels or passages d, d", and to extend into the cylindrical wall d into the main part of the cap at to a position at which communication is made with a transverse channel d". The opposite end 01' the channel d extends to the peripheral face of the cap a. where it is adapted for the reception of an air release screw-threaded plug similar to the plug j for the release of any fluid that may find access into the cavity e beneath the piston.

The lower part h of the casing 0 (Figures 1 and 2) may be formed separate from the main part, and the lower part may at its upper end be screw-threaded externally for engaging with an internal screw-thread at the lower end of the main part, and the joint then welded. The lower part of the casing thus constituted is adapted for the reception of a holding down ring c by which the casing may be secured to the well head flange in known manner.

Packing may be provided such as U leathers i at the external periphery of the piston a near its upper end, and on the inner face of the enlarged upper part of the casing 0 adjacent the lower end of the downwardly extending cylindrical wall d of the annular cap or closure fitting d.

The U leather i mounted upon the annular piston may be held in position by means of a retaining plate 2' which may be provided as illustrated in detail in Figure 5, the plate i being held in position by studs or screws 2' and provided with an integral downwardly extending circular flange i at intervals provided with vertical and transversely disposed holes 1' through which the fluid pressure medium may be accessible to the cavity in the U leather.

A protector in the form of an internally screwthreaded sleeve 12 may (Figure 1) be applied upon the upper end of the tube 12.

It will be understood that such an equipment as hereinbefore described is adapted for the insertion or withdrawal of connected sections of the drill stem or the like under conditions in which the pressure axially imposed upon the elastic sleeve f may be regulated as the conditions of operation may require.

A packer such as hereinbefore described of the static type (Figures 1 and 2) or rotary type (Figures 3 and 4) may have mounted in position beneath it a second packer as illustrated in Figure 6 comprising a massive elastic sleeve 1 within a casing m, similar to that described with reference to Figure 2 in the specification of the prior Patent No. 1,942,366, the sleeve 1 being similarly held within end rings m m and being adapted for the application of pressure externally thereof. The sleeve of the second or lower packer is not however adapted for axial compression oi the sleeve in the manner hereinbefore described. The second or lower packer may serve as an emergency or standing packer which can be brought into use either to enable the elastic sleeve 1 of the top packer to be replaced if necessary (when a static pack-oil would be effected by the lower packer) or in special cases where very high pressures are encountered in the well, the lower packer would then be available for supplementing the top packer. The elastic sleeve 1 of the lower packer may pack-oil and eflect a pressure tight seal up to pressures equal to that of the top packer, but the lower packer is intended mainly as a static pack-oil.

Natural rubber is affected adversely by contact with mineral oil or gas, and while natural rubber is especially advantageous as the material of the massive elastic sleeve from the point of view of resistance to wear and abrasion, a synthetic rubber is available which is practically oilproof. Thus it is in general preferred to provide the elastic sleeve 1 ofthe lower packer when used of the well-known oil resisting synthetic rubber which where the lower packer is intended or is used as a static pack-oil would not when so used be called upon to resist any tendency to undue wear or abrasion.

The second packer may be mounted within a stationary casing m which itself may be secured upon the well head flange, and may at its upper part be provided for the concentric mounting upon it of the lower flanged part or base of the casing c within which the axially compressible sleeve 1 is mounted, means being provided for access of the fluid pressure medium from a common source under regulation by valves n (Figure 6) for application axially upon the sleeve 1 of the top or first packer and externally of the periphery of the sleeve 1 of the bottom or second packer.

Such a double packer is indicated as exemplary of an equipment in which both kinds of elastic sleeve (1 and 1) may be used within a single casing or within superposed casings. The sleeve of the second or lower packer may however be reinforced to avoid excessive defamation under fluid pressure externally applied to it, and may be sertion or withdrawal ofconnected sections of the drill stem or the like. Thus the pressure to which the sleeve 1 of the lower or second packer may subjected may be relatively low and the sleeve the upper end ring m may itself be adapted for slight axial movement under the stress imposed p.30 may be relatively short or relatively thick, while I ure 6. Under the less drastic conditions of use of the second or lower packer the quality of the substance of the sleeve 1 need not equal that which is desirable for the sleeve 1 ofthe first packer. The sleeve 1 of the second packer may however be subjected to higher pressures to make a more efiective joint when connected sections of casing or the like are being held at the casing head.

In the use of the first packer soft soap or other lubricant may be used, and lubricant may also be applied within the cavity in the casing c in which it is mounted and around the external peripheral surface of the sleeve 1.

In carrying the invention into efiect in its application to a casing head equipment of rotary type as illustrated in Figures 3, 4 and 5, an annular piston a such as hereinbefore described may be employed that is similarly formed integrally with the upwardly extending tube b of the equipment, or otherwise connected at the lower end of the tube and mounted within a rotatable casing 9 in the lower part of which a massive elastic sleeve j is mounted, the rotatable casing a being adapted for rotation within a stationary.

casing c that may be secured in position on the well head flange 0 The rotatable casing g while being held substantially immovable axially is so connected to the tube b within it, that the tube b and the annular piston 11 are incapable of relative rotary movement with respect to the rotatable casing 9, but theannular piston a and tube b are axially movable with respect to the rotatable casing g to the extent necessary to apply pressure axially to the sleeve f, and under conditions in which the rotatable casing g together with the annular piston a and tube b are free to rotate within the stationary casing c, Thus the lower part of the rotatable casing g may be accommodated within a stationary casing c having an integral base part c by which it may be concentrically mounted upon the well head flange c, and the upper part of the stationary casing may be provided of a-larger internal diameter than the lower part for the accommodation of a central part 0 of the rotating casing which itself is provided of a larger internal diameter than its lower part a, and its upper part a, whereby an annular piston chamber e is provided within which the annular piston a is permitted a vertical movement under pressure of the fluid pressure medium on its upper face, the annular pistona being adapted to move vertically within the piston chamber c with a sliding fit, by which a fluid tight joint is maintained between the external face of the annular piston a and the internal face of the cylindrical wall of the piston chamber or cavity e formed in the central part of the rotating casing, suitable meansbeingprovided such as a U leather or U leathers i or the equivalent set within an annular cavity or cavities around the outer periphery of the annular piston a, at or near the upper end of the piston, and on the inner face of the enlarged upper part .of the casing 0 adjacent the lower end of the downwardly extending cylindrical wall d of the annular cap or closure fitting d. In the construction illustrated in Figures 3 and 4 the part (1 is separately formed from the cap d, the latter being screw-threaded into its upper end; there being provided an annular cavity surrounding the lowerpart of the cap adapted for the reception of a U leather i for ensuring a tight joint between the cap d and the cylindrical downwardly depending part d The cap or closure fitting d, d on being mounted in position may be locked by means of a locking screw the end of which engages the part d It will be understood that the massive elastic sleeve f may be formed and mounted in the lower part of the rotating casing in the same manner as hereinbefore described with reference to the non-rotatablecasing head equipment or packer illustrated in Figures 1 and 2. The lower part g of the rotatable casing 0 may be connected to the upper part a bya cylindrical wall a of larger diameter, to form the annular piston chamber e in position between. The upper part a of the rotatable casing a may be provided as an upwardly extending sleeve terminating in position beneath the cap d, and fitting snugly upon the upwardly extending tube b, which extends upward so that its upper end protrudes beyond the closure cap d, d. The tube b with the integral annular piston a is adapted to have free axial movementwithimthe rotating casing a. Any suitable means may be employed for the purpose such as an axial keyway or keyways and keys. Thus a number of axial channels or grooves a may be provided on the internal peripheral face of the upper part a of the rotating casing, one or more of which serve as keyways, while others are adapted to serve as channels for the fluid pressure medium. The cylindrical wall or enlarged middle part 9' of the rotating casing g is formed with a separate intermediate part or ring a by means of which the lower main part 9 may be connected to the part g For this purpose the part a is provided of tubular form with an internal flange 0' at its lower end and is internally screw-threaded by which it is adapt ed to be applied upon the reduced lower screwthreaded end of the main or middle part g so as to engage between the lower end of that part and the flange 9 an outwardly extending integral flange g provided at the upper end of. the lower cylindrical part a, an annular packing or washer g being interposed to ensure a tight Joint. The lower cylindrical part 9 at its lower end is provided with the upwardly extending flange h within which the annular cavity h." is formed for the reception of the lower end of the massive elastic sleeve f in the manner hereinbefore described. Between the upper end of the tubular part a and a shoulder formed externally of the part 9 an annular space is provided for the reception of a U leather 1 whose cavity is exposed at the peripheral face of the rotating casing. By such means a fluid tight joint is maintained. A ring of felt or other packing 0 may be provided within an annular cavity on the inner face of the lower part of the casing c and surrounding the lower part g of the rotating casing.

It will be understood that the annular piston a and the integral tube b together with the sleeve f are thus supported and enclosed within the rotating casing g (Figure3), so that these parts may be rotated within the stationary casing c. For

this purpose ball or other anti-friction bearings p,

p are provided adapted to permit the free rotation of the rotating casing a while under axial stresses due to the well pressure or to the weight of the parts rotated or to the weight of the connected sections of the drill stem or the like which may be supported upon the rotating casing when they are suspended from the well head in known manner. Such bearings may thus be provided between the lower end of the annular closure fitting (1, d and the upper face of the enlarged middle part 9 of the rotating casing, and between the lower face of the enlarged middle part g (formed by the fiange g of the tubular part g and the face of the inwardly extending flange c at the lower end of the stationary casing c, it being understood that pairs of bearing rings for the bearings p, p are mounted at the positions indicated.

The cap 11 of the annular cap or closure fitting d, (1 (Figure 3) is provided with a concentric hole through which the plain part of the tube b extends as in the construction described with reference to Figures 1 and 2, there being provided packing d a packing gland and a gland ring d. The gland ring d is however advantageously provided with a flange d of a'form such as illustrated in Figure 4 by which accommodation is afforded for a circular series of screw-threaded spindles q mounted within packed gland rings in the cap d, and adapted to be rotated for the application of pressure upon an internal gland ring q and the packing applied within an annular recess between the upper end a of the rotating casing and the inner peripheral face of the cylindrical wall d of the closure fitting d, 41 The upper ends of the spindles q are provided with a pair of oppositely disposed flat faces as'a means of engaging the spindles by a tool for their rotation and for the adjustment or compression of the packing. The lower part of the cylindrical wall d extends inwardly to form the lower part of the packing gland and the gland ring is advantageously provided near itsupper end with a series of radial holes 1 extending from the outer to the inner peripheral faces and with an annular groove or grooves on its outer peripheral face. Radial channels d are provided through which the fiuid pressure medium may pass under control into position beneath the cap d above the ring q and through the radial holes q into the inner annular space and thence through the channels or grooves g to issue into the upper part of the piston chamber or cavity e. I The radial channels :1 are at the outer end adapted by means of a fitting d of usual construction for connection with a hydraulic accumulator or other source of a fluid pressure medium.

Pressure releasing means similar to that provided in the construction illustrated in Figure 1 may be provided in the construction illustrated in Figure 3 for release of any fluid that may find access into the chamber or cavity e beneath the piston. Thus for this purpose inter-communicating channels may be provided in the piston a and tube b, opening at a position on the outer periphery at the upper end of the tube 12, and a screwthreaded closing plug similar to the closing plug a may be provided as a closure therefor, and the closure plug may be accessible when the rotating casing is stationary and when the closure plug is used, it being understood that instead the intercommunicating channels referred to may be open at a position on the outer periphery at the upper end of the tube b (Figure 3) or at the outer periphery of the cap :1 (Figure l).

The upper end of the tube protruding above the top of the stationary casing may be screwthreaded for the reception of a flange which may serve for carrying in equi-distant positions apart, two sets of screw-threaded bolts or studs that are vertically disposed parallel with the axis of the tube, one set of bolts or studs being adapted to enter screw-threaded holes provided on the outer part of the annular cap or fitting in positions coincident with the bolts or studs for the purpose of positively holding the .annular piston at the lower end of the piston chamber or cavity, or in the position which it may occupy under the prevailing pressure, so that thus the piston may be positively held in that position with the elastic sleeve under compression; while the bolts or studs of the other set are adapted to rest at their lower ends on the top face of the annular cap or fitting and thus positively to hold the annular piston in its uppermost position. Thus the first set of bolts tion of pressure axially imposed upon the elastic' sleeve under the conditions of operation, and with a view to ensure under those conditions substantial gas and liquid tightness.

It will Iurthermore be understood that all the parts require to be so constructed as to ensure the tightness of joints, and that the lower part of the annular piston chamber or cavity e may advan tageously be maintained open to the atmosphere. This may be done by the mere withdrawal of the release plug or plugs described.

The invention is not limited to the typical constructions that are hereinbei'ore described. Thus the invention is not limited to the use of a piston i and cylinder device for the application of axial pressure to the elastic sleeve. Thus instead of a piston, a fiexible diaphragm device may be employed.

adapted to be deformed under a considerable stress and to recover its original shape after deformation.

I claim:-

1. A casing head equipment for oil wells adapted for packing connected sections of the drill stem or other connected elements on their passing into or out of the well, consisting of a casing, a massive elastic packing sleeve through which said elements may pass, said sleeve being axially compressible and externally confined within a cavity in said casing, an annular piston and cylinder device within said casing, the cylinder being disend of said sleeve while the other end of said sleeve is held stationary, means for the admission of a fluid pressure medium within said cylinder for the downward movement of said annular piston and the axial compression and constriction of said sleeve for packing any of said elements for the time being within said sleeve, the constricted sleeve adapted to assume normal shape on the piston ceasing to be subject to the pressure of the fluid pressure medium.

2. A casing head equipment for oil wells adapted for packing connected sections of the drill stem or other connected elements on their passing into or out of the well, consisting of a casing having a lower cylindrical cavity therein and an upper cylindrical cavity of larger diameter, a massive elastic packing sleeve axially compressible and externally confined within said lower cylindrical cavity, an annular piston adapted to move vertically within said upper cylindrical cavity, the lower part of the annular piston being reduced in diameter whereby it may slide downward within the upper part of the said lower cylindrical cavity, said annular piston engaging the upper end of said sleeve while the lower end of said sleeve is held stationary, means for the admission of a fluid pressure medium into said cylinder and above said annular piston for the movement of the latter and the axial compression and constriction of said sleeve for packing any of said elements for the time being within said sleeve, the constricted sleeve adapted to assume normal shape on said annular piston ceasing to be subject to the pressure of the fluid pressure medium,

whereupon 'said sleeve ceases to pack any of said elements.

3. A casing head equipment for oil wells adapted for packing connected sections ofthe drill stem or other'connected elements on their passing into or out of the well, consisting of a casing, a massive elastic packing sleeve through which said elements may pass, said sleeve being axially compressible and externally confined within said casing and having a form such that its central axial hole is gradually increased in diameter towards its respective ends, the elastic substance of the sleeve thus extending inward at a position between its respective ends, a member disposed adjacent one end of said sleeve and adapted for rectilinear movement under pressure of a fluid pressure medium in direction towards said sleeve for its axial compression and constriction and for packing any of said elements for the time ceasing to be subject to the pressure of'the fluid Pressure medium.

4. A casing head equipment for oil wells adapted for packing connected sections of the drill stem or other connected elements on their passing into or out of the well, consisting 01' a stationary ca i 8 rotatable casing mounted within the stationary casing, the rotatable casing comprising a lower part and an upper part, the lower part having an internal diameter less than that of the upper part, a massive elastic packing sleeve that is axially compressible and disposed externally confined with the lower end held stationary within the lower part of the rotatable casing, an annular piston within the upper part of the rotatable casing, the external diameter of the lower end of said annular piston being less than that of the upper part, and the lower end of said annular piston being adapted to slide within the lower part of the rotatable casing in the axial compression of the sleeve, means for the admission 01' a fluid pressure medium in position above said annular piston for the downward movement of said annular piston for its axial compression and constriction and for packing any oi. said elements for the time being with in said sleeve, the constricted sleeve adapted to assume normal shape on said annular piston ceasing to be subject to the pressure of the fluid pressure medium.

5. A casing head equipment for oil wells adapted for packing connected sections of the drill stem or other connected elements on their passing into or out 0! the well, consisting of a stationary casing, a rotatable casing mounted within the stationary casing, the rotatable casing comprising a lower part and an upper part, the lower part having an internal diameter less than that of the upper part, a massive elastic packing sleeve that is axially compressible and disposed externally confined with the lower end held stationary within the lower part of the rotatable casing, an annular piston within the upper part of the rotatable casing, the external diameter of the lower part of said annular piston being less than that of the upper part, and thelower end oi. said annular piston being adapted to slide within the lower part of the rotatable casing for the axial compression of said sleeve therein, a closure cap for the stationary casing, means whereby the annular piston is permitted relative endwise movement with respect to the rotatable casing while connected for rotation therewith, said annular. piston having an upper tubular extension passing concentrically through the'upper part of the rotatable casing and through said closure cap, and means for the admission of a fluid pressure medium in position above said annular piston for the downward movement of said annular piston ior'its axial compression and constriction and for packing any of said elements tor the time being within said sleeve.

6. A casing head equipment for boreholes or wells, comprising a stationary casing, a rotatable casing within the stationary casing, an elastic packing sleeve externally confined within the rotatable casing, means by which the elastic packing sleeve is mounted with its lower end held from axial movement and its upper end capable of relative axial movement, means for the ap plication of a fluid pressure medium axially at .the upper end of the elastic packing sleeve and a second elastic packing sleeve mounted beneath the rotatable casing, the second elastic packing sleeve being held from rotation, means for the application of a fluid pressure medium externally of the second elastic packing sleeve and means for the control of a fluid pressure medium on the respective elastic packing sleeves.

LEWIS MERVYN CECIL SEAMARK. 

